open up a can of worms

open (up) a can of worms

To initiate, instigate, or reveal a situation that is or is likely to become very complicated or problematic or that will have a negative outcome. I worry that trying to tweak the existing system could open up a can of worms that we're not anticipating. The candidate opened a can of worms when he made those inflammatory comments. Now the entire election has been dominated by the topic.See also: can, of, open, Worms

open up a can of worms

discover or bring to light a complicated matter likely to prove awkward or embarrassing. informal 1998 New Scientist UN officials readily accept that they have opened a can of worms, and their guidelines will only have an effect, they say, if governments act on them. See also: can, of, open, up, Worms